Device for winding or unwinding material conducted in web or linear form, particularly groups of textile threads

ABSTRACT

Device for winding on or unwinding from a coil member, material conducted in web or linear form includes drive means for driving the coil member, and control means for maintaining constant tension in the material, the control means comprising sensing means for monitoring the tension in the material, switching means for controlling the speed of the drive means, and means including a delay mechanism for interconnecting the sensing means and the switching means so as to vary the speed of the drive means to maintain constant tension in the material.

United States Patent [1 1 Derichs Nov. 27, 19 73 DEVICE FOR WINDING OR UNWINDING MATERIAL CONDUCTED IN WEB OR LINEAR FORM, PARTICULARLY GROUPS OF TEXTILE THREADS [75] Inventor: Josef Derichs, Monchengladbach,

Germany [73] Assignee: W. Schlafhorst & Co.,

Monchengladbach, Germany [22] Filed: Jan. 21, 1972 [21] Appl. No.: 219,665

[30] Foreign Application Priority Data Jan. 23, 1971 Germany P 21 03 107.2

[52] US. Cl 66/86 A [51] Int. Cl. D04b 23/00, D04b 27/00 [58] Field of Search 66/86 A, 146

[5 6] References Cited UNITED STATES PATENTS 3,076,615 2/1963 Connors 66/86 A I 3,364,403 1/1968 Liebchen l 66/86 A 3,097,511 7/1963 Porter 66/86 A 2,720,093 10/1955 Lambach et al. 66/86 A FOREIGN PATENTS OR APPLICATIONS 844,453 8/1960 Great Britain 66/86 A 1,120,136 7/1968 Great Britain 66/86 A Primary ExaminerRonald Feldbaum Attorney-Arthur E. Wilfond et al.

[5 7] ABSTRACT Device for winding on or unwinding from a coil member, material conducted in web or linear form includes drive means for driving the coil member, and control means for maintaining constant tension in the material, the control means comprising sensing means for monitoring the tension in the material, switching means for controlling the speed of the drive means, and means including a delay mechanism for interconnecting the sensing means and the switching means so as to vary the speed of the drive means to maintain constant tension in the material.

2 Claims, 1 Drawing Figure DEVICE FOR WINDING OR UNWINDING MATERIAL CONDUCTED IN WEB OR LINEAR FORM, PARTICULARLY GROUPS OF TEXTILE THREADS The invention concerns a device for winding or unwinding material conducted in web or linear form, particularly groups of textile threads, having a drive for the coil form, such as a warp beam, for example, which is controlled in order to maintain constant tension in the material or threads.

Devices have been known heretofore, wherein the deflection of a sensing member, such as a compensating roller, for example, which varies during the winding process, is utilized to control the drive for the warp beams, an adjusting motor which changes the transmission ratio of a continuously variable transmission for the drive of the warp beams until the control deviation is removed being actuated, for example, by the deflection of the sensing member. In the process, however, overcontrol occurs, which can result in continuous hunting or oscillating of the control. It is very difficult to keep the amplitude of theseoscillations as small as possible as it is influenced to a considerable degree by the initial conditions as well as by the design of the control circuit, among other things.

It is accordingly an object of the invention to provide device for winding or unwinding material conducted in web or linear form, particularly groups of textile threads, which has an improved control that automatically reduces the amplitude of the oscillations so that the control process is thereby stabilized.

With the foregoing and other objects in view, there is provided in accordance with the invention device for winding on or unwinding from a coil member, material conducted in web or linear form comprising drive means for driving the coil member, and controlmeans for maintaining constant tension in the material, the control means comprising sensing means for monitoring the tension in the material, switching means for controlling the speed of the drive means, and means including a delay mechanism for interconnecting the sensing means and the switching means so as to vary the speed of the drive means to maintain constant tension in the material.

The invention is particularly effective if the control circuit is designed as a three-point control. In accordance with another feature of the invention, the delay means comprises a speed-proportional damping member and two restoring springs, one of which is operatively connected in parallel with the damping member and the other of which is so disposed that it exerts a restoring force on the switching means.

In warp knitting machines, it has been known to provide the warp beam with a band brake which brakes the rotation of the warp beam which is effected by the pull f the thread. Variation in the braking force accordingly occurs as a function of the position of the threadtensioning rocker which additionally serves for compensating the thread tensions caused by the knitting movement. This system has the disadvantage, however, that the warp threads are particularly heavily stressed.

The invention of the instant application presents the possibility, in warp knitting machines such as Raschel knitting machines, particularly, which are equipped with warp beam drives, that the thread-tensioning rockers, which are provided for the compensationof the thread tensions caused by the knitting motion, can be additionally used for the control of the warp beam drives. Accordingly, the thread-tensioning rocker, in accordance with a further feature of the invention, is coordinated with that part of the damping member that is of greater mass, for example, by a rotationally fixed connection between the damping member and the pivot shaft of the thread-tensioning rocker, while that part of the clamping member having the smaller mass is connected to the switching means and to a restoring spring which counteracts the biasing effect of another restoring spring disposed between the threadtensioning rocker and the switching means. Superimposed on the change in position of the threadtensioning rocker caused by the varying diameter of the beam, however, are further changes in position caused by the movement of the knitting tools. The effect of these additional position changes of the threadtensioning rocker upon the control circuit can be avoided with the aid of the invention of the instant application by, for example, dimensioning the drive motor of the adjusting transmission so that it does not react to oscillations of the thread-tensioning rocker of short duration.

Other features which are considered as characteristic for the invention are set forth in the appended claims.

Although the invention is illustrated and described herein as embodied in device for winding or unwinding material conducted in web or linear form, particularly groups of textile threads, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.

The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understod from the description of the single FIGURE of the drawing which is a diagrammatic perspective view of the device for winding or unwinding from a coil member material conducted in web or linear form, in accordance with the invention.

Referring now to the drawing, there is shown therein a switching member 1 provided with two contacts 10 and l l, which switch on a conventional adjusting or positioning motor 24 by means of a switching vane 18 which is adjustably secured to a shaft 9. A sensing member 2 in the form of a thread-tensioning rocker 7 is rigidly connected through arms 17 to the rotating shaft 12. A lead element 3 is provided between the sensing member 2 and the switching member 1, and includes a damping member 4 which, in the illustrated embodiment, is formed of a tank rigidly connected to the rotating shaft 12 and filled with oil as damping medium. A damping member 8 constructed as a paddle is immersed in the tank 4 and also rigidly connected to the shaft 9. A spiral restoring spring 5, which is secured at its inner end to the shaft 9 is connected at its outer end to a pin 19 extending from the damping tank 4. A second spiral restoring spring 6 is secured at its outer end to a stationary support block or beaming stand 20.

During the knitting process, a thread group 16, which is guided over the thread-tensioning rocker 7, is fed in the direction of the arrow 21 from one or more warp beams 25 to non-illustrated knitting tools. The change in the thread tension which is characteristic for the consumption of thread by the knitting tools produces an oscillating motion of the thread-tensioning rocker 7 indicated by the double arrow 52. The basic tension for the warp thread group 16 is determined or controlled by a helical tension spring 14 which is connected at one end thereof to a disc 13 that is firmly secured to the pivot shaft 12, the other end of the spring 14 being connected to an adjusting knob or wheel 15. Similarly, as the thread-tensioning rocker 7 oscillates back and forth in the directions of the double-headed arrow 22, the damping tank 4, which is connected to the pivot shaft 12, is reciprocated in the directions indicated by the double-headed arrow 23. The damping paddle 8 also performs this oscillating motion in a similar manner and, accordingly, causes the switching vane 18 to swing, as desired, into the region of the contacts 10 and 11. As mentioned hereinbefore in the introduction to this specification, the drive motor 24 of the positioning or adjusting drive does not react to these brief or shortterm oscillations. Only if contact 10 or 11 respectively is in communication for an extended period of time with switching vane 18, does the motor 24 drive the positioning or adjusting transmission. This operation always occurs when, due to a decreasing diameter of the warp beam 25, the tension of the thread increases, and the thread-tensioning rocker 7 is further deflected for an extended period of time. As soon as the increased thread tensioning has been compensated by increasing the driving speed for the warp beam 25, the threadtensioning rocker 7 can deflect to the opposite side for an extended time period due to overcontrol, and the switching vane 18 can consequently communicate with the contact 1 1 so that the drive motor 24 causes the positioning or adjusting transmission of the warp beam 25 to operate in the opposite direction. The restoring springs and 6, which act in opposite directions on the damping members 4 and 8, respectively, accordingly decrease the amplitude of the oscillations automatically, so as to effect a damping of the amplitude of the oscillations during the control process.

The damping members 4 and 8 disclosed in the illustrated embodiment can, of course, be also replaced by similarly acting elements, such as an eddy current brake, for example. In order to attain behavior of the lead element 3 that is as ideal as possible, the mechanical components should be provided primarily with little mass. For this reason, the damping tank 4 with the greater mass would also be firmly connected to the thread-tensioning rocker, so that the-mass of the damping tank 4 is not an important factor for the time response or behavior of the delay member 3.

Although the invention is applicable with particular advantage for the control of the warp beam drive in warp knitting machines, the basic idea of the invention is, neverthelss, not confined to this field alone. The invention is also applicable advantageously to other machines which serve for winding and unwinding material conducted in web or linear form, such as, for example, beaming machines for warp threads or foils wherein the material is fed at constant speed.

I claim:

1. An apparatus for winding on or unwinding from a coil member, material conducted in web or linear form, comprising: drive means for driving the coil member; control means in communication with the drive means for maintaining constant tension in the material as such material is being unwound, said control means including sensing means for monitoring the tension in the material, switching means connected to the drive means for controlling the speed of said drive means; and lead element means disposed between said sensing means and said switching means, including a speedproportional damping means, first and second restoring springs, the first of which is operatively connected in parallel with said damping means and the second of which is operatively connected to said switching means for exerting a restoring force thereon to thereby adjust the speed of said drive means so as to maintain constant tension in the material.

2. An apparatus according to claim I, wherein: the first spring is a restoring spring disposed to act in direction opposite to said second spring; said first spring being disposed between a thread-tensioning rocker and a switching arrangement, said damping means comprising a first part of relatively large mass and a second part of relatively small mass, said first part being in cooperative working relationship with said thread-tensioning rocker, and said second part being operatively connected to said switching means and to said second spring. 

1. An apparatus for winding on or unwinding from a coil member, material conducted in web or linear form, comprising: drive means for driving the coil member; control means in communication with the drive means for maintaining constant tension in the material as such material is being unwound, said control means including sensing means for monitoring the tension in the material, switching means connected to the drive means for controlling the speed of said drive means; and lead element means disposed between said sensing means and said switching means, including a speed-proportional damping means, first and second restoring springs, the first of which is operatively connected in parallel with said damping means and the second of which is operatively connected to said switching means for exerting a restoring force thereon to thereby adjust the speed of said drive means so as to maintain constant tension iN the material.
 2. An apparatus according to claim 1, wherein: the first spring is a restoring spring disposed to act in direction opposite to said second spring; said first spring being disposed between a thread-tensioning rocker and a switching arrangement, said damping means comprising a first part of relatively large mass and a second part of relatively small mass, said first part being in cooperative working relationship with said thread-tensioning rocker, and said second part being operatively connected to said switching means and to said second spring. 